Manhole construction



y 3, 1935- J. L. GEHRIS 2,009,132

MANHOLE CONSTRUCTION ori inal Filed Nov. 10', 19:52. 2 Sheets-Sheet 1wuiiminm Jul 23, 1935. J, L, EHRls 2,009,132 7 MANHOLE CONSTRUCTION IOriginal Filed Nov. 10, 1932 2 Sheets-Sheet 2 5 20 mm" 5 51.2445 i4 J 50A HHHWHII a Z5 0 24 26 ojflj 21 Z l a1 26 10 i4 29 Patented July 23,1935 PATENT OFFIQE 2,009,132 MANHOLE GQNSTRUCTION Jeaeplr L. Gehrls,Reading, Pa.

Application November 10, 1932, Renewed lune 6,

Claims.

My invention relates to inlet devices for sewers or the like and hasparticular reference to manhole cover structures that usually includemetallic casings or housings permanently built into 5 the pavingstructure of the street and a detachable cover plate.

A purpose of the invention is to provide a device of the characterindicated easy and inexpensive to manufacture and well suited to theneeds of service.

A further purpose isto provide a manhole cover device that will notrattle under automobile traffic.

A further purpose is to provide a cover plate with virtually a three-legsupport upon its casing, the legs preferably to comprise arcuatelyspaced downwardly directed arcuate pads integral with the cover and torest upon spaced portions of a cooperating inward flange of the casing.

A further purpose is to reinovably downwardly wedge the cover to itsseat at opposite sides thereof, preferably strongly spring pressingrelatively movable wedge portions of the cover apart into wedge recessesof the casing on opposite sides thereof, one of the said relativelymovable portions comprising preferably a spring latch and the other themain body of the cover.

A further purpose is to locate a spring latch in a radial perforationthrough one of the three legs or pads, spring wedging the cover down toits seat at the one arcuate leg or pad and on the other side to providea wedge extension from the cover at a part thereof midway between thetwo other pads whereby at the said other side the downward pressure uponthe cover, efiected by the cooperating wedge surfaces, is supportedequally upon the said two other arcuately spaced legs or pads.

A further purpose is to provide a cover of the character indicated witha novel and particularly simple and convenient form of latch mechanism.

A further purpose is to provide a cover with a relief valve to permitautomatic relief of any pressure within the sewer incident to theaccumulation or explosion of sewer gases or the like.

A further purpose is to combine a casing, a

cover and a lock holding the cover rigidly to itscasing with a pressurerelief valve, thereby avoiding danger of the casing and whole structurebeing blown out of its setting in the event of a gas explosion withinthe sewer closed by the structure.

Further purposes will appear in the specification and in the claims.

Serial No. 641,988 1935 I have elected to show one form only of myinvention, selecting a form however that is practical and eflicient inoperation and which well illustrates the principles involved.

Figure 1 is a top plan view of structure embodying a desirable form ofmy invention.

Figure 2 is a vertical section of Figure 1 taken upon the line 2-2thereof and illustrating the latching mechanism with a. fragmentarydotand-dash showing of the point of a pick adapted to release the latch.

Figure 3 is a fragmentary portion of Figure 2, the latch being closed inFigure 2 and being pushed back by the inserted pick in Figure 3.

Figure 4 is a view corresponding generally to Figure 2, but with theparts together in Figure 2, separated in order to show both members moreclearly and with the pressure relief valve closed in Figure 2 shownraised or open in Figure 4.

Figure 5 is a bottom plan view of the cover member and corresponds to aview taken upon the line 5-5 of Figure 4.

Like numerals refer to like parts in all figures.

Describing in illustration and not in limitation and referring to thedrawings:

One of the aims of the present invention is to provide a manhole coverand casing structure that will not rattle when subjected to the heavytraflic of rapidly moving automobiles.

In the past the manhole covers have very generally or very frequentlyfailed to seat sufficiently uniformly to prevent them from heavyknocking and rattling when traversed by rapidly moving cars, the platesstriking perhaps first on one side, then on the other, being supportedat indefinite portions of their circumferences, sometimes at one portionand sometimes at one or more other portions thereof.

I provide a manhole cover with virtually a three-leg support andstrongly wedge the cover down to its seat at opposite points on theperiphery, respectively in the middle of the engaging portion of one ofthe legs and midway between the other two legs.

I provide each leg with a very considerable peripheral extension alongits line of engagement with the casing, an extension suitably nearlysixty degrees, and as a result of this and. of the downward wedging ofthe cover at the middle of one leg and at a portion midway between theother two legs, the cover maintains its seat without rocking even whensubjected to heavy traffic. v The three-leg support of the manhole coveris very important because the cover and casing are ordinarily both roughcastings, which cannot economically be machined. A full peripheralsupport, or a four-leg support, five-leg support, etc., is thereforelikely to rock, due to irregularities in the cast surfaces, or due torust or dirt between the cover and the casing.

While the manhole cover and easing may be of any suitable shape, theyare frequently round, and I am accordingly illustrating an annularstructure. It will be understood however, that by using language aptlydescribing a circular manhole, I do not intend to exclude manholes ofother shapes.

The illustrated embodiment of my invention comprises a manhole casing 5and a cover 6, the casing to be built permanently about a street inletto a sewer or the like, the top of the casing being usually even withthe surface of the street.

The casing circumferentially surrounds the cover and carries the coverupon three arcuately spaced portions of an inward flange 1, the bottomof the cover being suitably provided with three arcuate pads or legs 8which seat on the corresponding spaced portions of inward flange 1 ofthe casing.

The flange 1 is spaced downwardy from the top of the casing a sumcientdistance for even registry of the tops of the casing and cover and maydesirably have greater inward extension under the arcuate pad or legsportions 8 of the cover than intermediate these portions.

The cover is suitably ribbed on bottom and top as at 9 and I0respectively and when used to close an opening into a sewer in whichthere may be danger of sewer gas explosions, it is desirably providedwith a central opening II to be normally closed by a pressure reliefvalve l2.

The need for a pressure relief valve is principally incident to my rigidfastening of the cover down to the casing. A vertically loose cover canitself act as a pressure relief member, lifting to permit escape of thegaseous products of any explosion within the sever, but with my coverrigidly fastened to the casing, the whole casing might with a severeexplosion be blown from its setting without my safe-guarding reliefvalve.

The stem of the valve I2 is shown supported and guided by a hub l3 thatis connected by radial ribs M to the body of the cover.

The valve I2 is preferably spring pressed downwardly, as by a spring l5surrounding the stem and compressed between the hub and a suitable keyl6 through the lower end of the stem. The key I6 is held in place by theedges of a flanged washer l6.

The valve seat is suitably relieved at three arcuately spaced portionsI! of its circumferential length. This clearance along spaced portionsof the valve avoids or lessens any danger of the valve either stickingor rattling in its seat, the support being along three preferablyuniformly spaced portions of the circumference.

The cover 6 in closed position has a spring pressed wedge interlockingwith downwardly directed abutments l8 and I! at diametrally op positesides of the casing, the interior of the casing being diagonallydownwardly, recessed to provide these abutments and to receive radiallyprojecting wedge tighteners 20 and 2| carried by the cover.

The wedge tightener 2| isi rigid extension from the body of the coverand preferably integral therewith and the other wedge tightener 20 theouter end of a spring-pressed plunger 22 herein called a latch and hasthe double function of latching and wedging the cover into closeconnection with its supporting seat.

The latch 22 is mounted in an upward recess 23 in preferably the middleof one of the pad or leg portions 8 of the cover, the pad being extendedradially inward at 24 to case the rearward portion of the latch andprovided with downward lugs 25 to receive a retaining pin 26. A seat 21is provided on the bottom of the cover for the inner end of a strongspring 28, the forward end 'of the spring seating in a. suitably formedrecess at the inner end 21, of the latch member.

The pin 26, put in after the insertion of the latch member, has thedouble function of holding the body of the latch and of limiting theforward movement of the latch after the cover has been removed or liftedfrom the casing (Figure 4).

The spring 28 is compressed between inwardly and outwardly directedabutments of the latch and cover body and strongly presses the latchoutwardly from the body and thereby strongly presses the wedgetighteners apart to engage the casing at diametrally opposite sides, oneof these wedge surfaces being merely an extension suitably in tegralwith the main body of thecover and the other the outer end of the latch22.

The latch tightens under the heavy pressure of its spring whenever thecover plate is subjected to vibration, e. g. vibration incident totraific over the cover, and my combination of three-leg support andstrong downward wedging of the cover at its opposite sides secures acontinuous tight seating and an avoidance of rattle even under heavytraffic.

For more easy angular registry between the cover and its casing, Iprovide one of the members, suitably the cover, with a small angularprojection 29 to fit a registry recess 30 in the other member. Theregistry projection (or recess) of the cover should be located directlyabove the middle of the wedge projection 2| and the corresponding recess(or projection) of the casing at the middle of the casing recess thatreceives the wedge member 2! of the cover. This registry projection onthe cover or on the casing is preferably dimensioned to keep the coverfrom seating except when in proper registry with the casing.

In replacing a cover, a workman positions the cover so that theprojection 29 is opposite the recess 30, drops this side of the cover toits seat, then pulls the cover until the projection 29 and recess 30register, when the other side of the cover drops and latches to place,the spring latch automatically locking the cover down to its seat.

The wedge surfaces at the end ofv the latch are such that the latch doesnot reach its full outward movement except when the cover has beenremoved (Figure 4). The cover is thus wedged downwardly at the latch andthe cover is spring pressed to firm engagement with the casing on theside of the cover opposite the latch.

The latch and cover are perforated at 3| and 32, these perforationsbeing relatively offset as clearly shown in Figure 2 for retracting thelatch with the point of a pick or the like.

To remove the cover, the point of a pick may be inserted through theperforations 3| and 32, as, for example, to the position shown in Figure3. This insertion pulls back the latch with or without leverage of thepick and permits the workman to lift off the cover by means of the pick,

the insertion of the pick having pushed back the latch. a

It will be evident that the three-leg support or my invention may beobtained by placing projections on the cover as illustrated, by placingprojections on the casing or by placing cooperating projections on boththe cover and casing.

The three-leg support is desirable, even without latching down of thecover, but is much more desirable where the cover is latched andpreferably continuously wedged down. With three-area support of thecover, and with resilient wedging down of the cover, an initially stablestructure is more firmly held each time it yields under vibration orwear.

My relief valve permits ready escape of pressure, so that dangerouspressures are not likely to build up and damage due to explosions isminimized.

In view of my invention and disclosure variations and modifications tomeet individual need or particular whim will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of myinvention without copying the structure shown, and I therefore claim allsuch in so far as they fall within the reasonable spirit and scope of myinvention.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a manhole construction, a casing adapted to surround a cover andhaving an inwardly projecting flange to support the cover, there being apair of peripherally spaced downwardly directed abutments in the casingand a cover resting upon the flange within the casing, there being aprojection from the cover cooperating with one of the abutments andthere being a spring-urged wedge, movable with respect to the cover andcooperating with the other abutment to urge the cover downward, thewedge being accessible from above to withdraw the wedge from operativeposition.

2. A manhole construction comprising a casing which surrounds and isflush at the top with a cover, the casing having an inwardly projectingflange, and a cover which rests upon the flange, the casing havingdiametrally spaced downwardly directed abutments of wedge form, therebeing a wedge projection from the cover rigid with respect to the cover,cooperating with one of the abutments, a movable wedge slidable radiallyof the cover and, in operative position, cooperating with the oppositeabutment, there being an opening in the cover so that the movable wedgeis slidable by a worker above the cover, and a stiff spring urging themovable wedge against its abut ment, whereby the wedge projection andthe movable wedge cooperate to hold the cover tight in the casing.

3. A manhole construction comprising a casing which surrounds and isflush at the top with a cover, the casing having an inwardly projectingflange and a pair of peripherally spaced downwardly directed abutments01 wedge form, and a cover which has three spaced legs resting upon theflange within the casing, there being a rigid wedge on one side or thecover cooperating with one abutment, a movable wedge peripherally spacedfrom therigid wedge, slidable in a radial direction and cooperating withthe other abutment, rigid guides upon the cover to hold the movablewedge against lateral movement. and a spring urging the movable wedge toits position of cooperation with its abutment, an opening being providedin the movable wedge through which a tool can be inserted to move themovable wedge and another opening being provided in the cover tocooperate with the opening in the movable wedge.

4. In a manhole construction, a casing adapted to surround a cover,which is flush at the top with the cover, the casing having a horizontalflange projecting inwardly from the casing at a point intermediatebetween the top and the bottom of the casing, there being a pair ofopposite downwardly directed abutments in the casing above the flange,and a cover resting upon the flange, having a rigid projection oi wedgeformation cooperating with one of the abutments and having a movableprojection of wedge formationcooperating with the other abutment, themovable projection being guided by walls on the lower part of the coverso as to move radially and being spring urged towards its radiallyoutermost position, the movable projection being accessible from abovethe cover to operate it.

5. In a manhole construction, a relatively cooperating casing and cover,the casing having a recess and the cover having a projection to secureproper annular registry, the cover having three points of engagementwith thecasing for maximum stability and having a pair of cooperatingwedges which engage abutments upon the casing, one of said wedges beingspring urged outwardly with respect to the other, whereby change in theposition of the cover with respect to the casing due to wear on one ofthe three points of support of the cover will not render the coverunsteady due to the action of the wedges in continuously maintaining thecover firmly seated in the casing.

JOSEPH L. GEHRIS.

